Valve unit for non-lube air compressors



f Dec. 12, 1967 S. F. KING VALVE UNIT FOR NoN-Lum AIR coMPREssoRs 2Sheets-Sheet l Filed June 24, 1965 @NEX Dec. 12, 1967 s. F. KING VALVEUNIT FOR NON-LUBE AIR COMPRESSORS 2 Sheets-Sheet 2 Filed June 24, 1965 JQ43 A fram/F Y United States Patent O 3,357,449 VALVE UNIT FOR NGN-LUBEAIR COMPRESSORS Smith F. King, Franklin, Pa., assigner to ChicagoPneumatic Tool Company, New York, N.Y., a corporation ot' New .erseyFiled .lune 24, 1965, Ser. No. 466,532 7 Claims. (Cl. 137-5111) Thisinvention relates to ring plate valve units for use in air compressorsof the piston type, particularly non-lube air compressors.

The present invention represents an improvement o-ver the valve unitsdisclosed in my Patent 3,177,893, dated Apr. 13, 1965. The subject valveunits are of simpler construction and display improved operatingcharacteristics over the valve units of my prior patent. Moreparticularly, the valve units of the present invention utilize discguides each having a single cylindrical guiding portion which ispositionable in a pilot hole arranged in the valve seat. Such anarrangement allows for provision of a iiat surface on the keeper beneatheach disc guide, which ilat surface will absorb impact load upon valveopening thus greatly reducing the incidence of disc guide breakage- Longlife of the disc guides is achieved by use of a special material whichis substantially wear resistant.

The main object of this invention is to provide an improvement in valveunits and more particularly in valve guide means for use in valve unitsof the type used in air compressors.

A more specic object is to provide a valve guide means of simpliiiedconstruction and improved operating characteristics.

Another object is to pro-vide a valve guide means having superior wearcharacteristics.

The foregoing and other objects and advantages of this invention willappear more fully hereinafter from a consideration of the detaileddescription which follows, taken together with the accompanying drawingswherein an embodiment of the invention is illustrated. It is to beexpressly understood, however, that the drawings are for purposes ofillustration and description and they are not to be construed asdefining the limits of the invention.

In the accompanying drawings:

FIG. 1 is a cross section of a ring plate valve unit ernbodying theinvention and showing the valve unit seated in the intake opening of anon-lube type air compressor of the piston type, only a fragmentaryportion of the cornpressor being shown;

FIG. 2 is a section taken on line 2-2 of FIG. l;

FIG. 3 is a section taken o-n line 3 3 of FIG. l;

FIG. 4 is an elevational view of the guide member;

FIG. 5 is a bottom plan view of the guide member; and

FIG. 6 is a fragmentary sectional view of the valve unit, showing thering plate valves in open condition.

In the drawings is disclosed a valve unit, generally designated 10,embodying the invention. This unit is shown seated in the intake opening11 of a conventional nonlube type air compressor, generally designated12. The compressor is of a type having a piston 13 reciprocable in achamber 14. As the piston moves on its intake stroke in one direction itdraws air through the valved intake opening 11 into the piston chamber;and as the piston moves in the opposite direction, it forces the airthrough a valved discharge opening (not shown). The function of anon-lube type compressor is to supply oil-free compressed air throughits discharge end. While the valve unit embodying the present inventionmay also be used in lube type compressors, it is particularly suited foruse in the non-lube type compressor because of the wear resistance ofits parts.

The valve unit includes (FIGS. 1, 2, 3) a housing or or body comprisinga circular valve seat member 15 and bined thickness of the base 39 of aguide and the thicka complementary mating valve keeper member 16 tightlybolted to the seat member in face to face contact by means of a screw17. When the valve unit is assembled in the compressor, as in FIG. l, areduced cylindrical portion 18 of the keeper member Iits into the intakeopening 11, and an annular shoulder 19 of the keeper member rests upon acomplementary shoulder 21 of the compressor housing. The valve unit isanchored fast in the intake opening 11 by means of a conventional sleeveclamp 22 which sleeves over a reduced cylindrical portion 23 of the seatmember and presses tightly -upon an annular shoulder 24 of the latter.

The keeper member 16 further has an inner level face 25 which is held bythe screw 17 in contact with an opposed inner level face 26 of the seatmember. Formed in the face 25 of the keeper member is an annular shallowairflow channel or recess 27 which communicates by means of a pluralityof recessed arcuate ports 28 through the bottom of the keeper with thepiston chamber 14 of the air compressor, as in FIG. l. Recessed in theface of the seat member (RIGS. l, 3) is a pair of annular air-flowchannels, comprising an inner channel 29 and an outer channel 3i). Thesechannels are concentric to one another and are spaced apart by anannular portion 31 of the face of the seat member. These channels arecentered above and are concentrically arranged relative to the air-ilowrecess 27 so as to open directly into the latter. The radial extent ofthe air-flow recess 27 of the keeper member is greater than the combinedradial extent of channels 29, 30, and the space 31 between them. Aplurality of arcuate ports 32 formed in the body of the seat membercommunicate channels 29, 31B through the outer face 33 of the seatmember whereby intake air entering through a port 34 of the clampingsleeve may iiow through the arcuate ports 32 into the channels 29, 30.Ports 32 are separated from one another by radial rib portions 35 of thebody of the seat member.

The area of the inner face of the seat memberv bordering channels 29, 30defines a seat which is commonv to a pair of radially spaced concentricring plate or disc valve elements 36, 37. These valve elements areconfined between the keeper and seat members for axial movement in theair-ow recess 27. These valve elements are also concentric with channels29, 30, and the aireflow recess 27. The valves control flow of intakeair from channels 29, 30 of the scat memberto the air ow recess 27 ofthe keeper member. Valve 36 is adapted to seat flat over channel 29;land Valve 37 is adapted to similarly seat over channel 30. These valvesare rigid and are formed of hardened stainless steel. The structuralnature of the valves avoids not only rusting and distortion thereof, butalso avoids consequent undesirable valve seating.

A plurality of spring biased valve guides 38, here three in number andspaced circumferentially degrees apart, yieldably hold the valves inseated condition (FIGS. 1, 2, 4, 5). Each guide comprises a flatsurfaced circular base portion 39 from the upper surface of whichaxially extends a cylindrical lreduced guide stem 41. Each guide iscommon to both valves. The stem of each guide passes slidably betweenboth valves and extends with a slide lit into a cylindrical bore 42centered between chan# nels 29, 30 of the seat Imember. The guide stern41cooperates with the bore 42 in providing a xed path of movement forthe guide 38. And the guide in turn guides movement of the valves in atxed axial path.

Both valves lie iiat in a common plane upon the upperN surfaces of thebase portions 39 of the guides. Each guide is yieldably biased by a coilspring 43 toward the seat member to hold both valves seated. The airiiow recess 27 has a shallow depth substantially equal to the comisprovided in the keeper member at the bottom of the annular recess 27 toreceive the base portion of a corre-r sponding guide. Each well iscentered in the recess and is coaxial with the corresponding vguide bore42. The well is slightly greater in diameter than the base of the guidesoas to allow rapid escape of air from the well as the guide moves downinto it. By means of this arrangement, air d oes not become trapped atthe bottoni of the well to check movement of a guide or the valves; anda vacuum is not created in the well below the guide to retard returnmovement of the valves and guide. The extent to which the valves open islimited by the bottom wall 45 (FIG. 6) of the air ow recess. The valvesextend slightly beyond the periphery of the guide base and are adaptedto limit upon the bottom wall of the recess 27 as the guide limits atthe bottom of its well. So that the valves will not tilt relative to theguides as they move from their seat, a major portion of the radialextent of each valve rests upon the surfaces of the guide bases 39.

The axial depth of each well is preferably not greater than that of theguide base 39 so that when the latter is fully received in the well, theupper surface of the guide base will lie flush with the bottom wall 45of the air flow recess 27 and the marginal outer portion of the valveswill overlie the bottom wall of the air ow recess. The biasing spring 43is a coil spring which is seated at its bottom end in an annular groove46 formed in the bottom of the well and is seated at its upper end in anannular groove 47 formed in the underside of the guide base. The groovesare coaxial with the guide. The spring grooves provide a desirableadvantage in that they maintain the spring in coaxial relation to theguide and as a consequence prevent the spring from wandering about thewell. By means of this arrangement, the biasing force of the spring onthe guide is centered on the latter.

In the operation of the device: as the piston 13 moves on an exhauststroke, a resultant strong suction action is created in the pistonchamber; In response to this action, intake air rushing rapidly throughchannels 29, 30 of the seat member forces the valves to open conditionagainst the resistance of the spring biased guides 38. The incoming airthen flows to the air-flow recess 27 and through the ports 28 of thekeeper member to the piston charnber 14. Toward the end of the exhauststroke of the piston, the springs 43 are caused to relax whereupon theyact through the guides to return the valves to seated condition. In thisopening and closing action the valves and guides do not move relative toone another but move together as a unit. Accordingly, there is nofriction action between them. As the valves move away from their seat,they carry the guides with them against the resistance of the springs;as the guides are returned by the spring, they carry the valves withthem. The stem portion 41 of the guide moves at all times in its bore 42as the valves move; it restrains the valves against relative radialmovement; and the base portion 39 supports the valves as they move. Bymeans of this arrangement, the valves are guided in their movementy atall times relative to their seat.

During operation of the compressor, the piston 13 cycles at high speed.Accordingly, it is desired `that the valves open and close as nearly -aspossible in timed relation to the cycling of the piston to obtain adesirable high efficiency of compressor operation, It has been foundthat if the biasing springs 43 are too strong, they will cause thevalves to close too soon, and if they are too Weak they will undesirablyslow closing of the valves. It has been found that desirable results areobtained in the operating efficiency of the compressor when the vbiasingsprings 43 are just strong enough to hold the valves closed f upon theirseat when the compressor is at rest.

When the valves are opened by the in-rushing air, each guide is forcedinto contact with the bottom 48 of its well.

So as to provide room for retraction of the spring, groove 46 is ofsufficient depth to fully receive the spring when the guide is seated atthe bottom of the well, as appears in FIG. 6.

In view of the limited resistance offered by the springs 43, the forcewith which the valves are opened by the inrushing air causes the guidesto impact forcefully against the bottoms of the wells. The bottom 48 ofeach well is flat and level and cooperates with the corresponding atunderside of the guide base to uniformly absorb the impact and thusprevents damage to the guide. As a further protective measure to avoidimpact damage to the guide,

the groove 46 at the bottom of the well is deep enough to fully receivethe spring asy the guide impacts against the bottom of the well. Thisenables the base 39 of the guide to impact evenly over the correspondingat bottom of its well and thus spread the reaction of the impactingforce evenly over the surface of base 39 of the guide.

Because the valves and valve guides move together as a unit, there is nowearing action of the valves or the guides relative to one another.However, there is a sliding relation yof the stem portion 41 of eachguide' relative to the wall of its bore 4Z. To avoid frictional wearhere, the wall of the bore has a smooth bearing surface and the guide issubstantially friction-free in that it has an inherently greasy orslippery surface. Here, the guide is a one-piece structure. It ispreferably formed from material which is light in weight, tough, has aninherently greasy or slippery property, and `which can withstand thehigh temperatures encountered in compressor applications. A plasticcommonly known as Teflon is suitable for this part because it has a lowcoeicientof friction without lubricant; its mechanical properties aremaintained at temperatures of 450500 degrees F.; it is substantiallyinert to chemical action; and it is light in weight. It is preferred,however, that the Teon be blended with a suitable filler, such as glass,to give it added strength and rigidity.

While an embodiment of the invention has been illustrated and describedin detail, it is to be expressly understood that the invention is notlimited thereto. Various changes might possibly be made in the designand arrangement of the part without departing from the spirit and scopeof the invention. It is intended, therefore, to claim the invention notonly as shown and described, but also in all such forms andmodifications thereof as may be reasonably construed to fall within thespirit of the invention and the scope of the appended claims.

What is claimed is:

1. In a valve unit for a piston type air compressor, comprising a valveseat member having an inner level face and a pair of concentric airintake channels recessed in said face, a keeper member complementing theseat member having an inner level face and having an annular channelrecessed therein in opposed parallel relation to the intake channels,and a pair of concentrically arranged ring plate valves axially movablein the annular channel to open and closed condition over the intakechannels,

the improvement comprising: a plurality of wells spaced.

circumferentially equally apart at the bottom of the annular channel ofthe keeper member and each centered relative to the intake channels, aseparate guide bore coaxial with each well formed in the seat memberbetween the intake channels, a valve guide associated with each Wellhaving an annular base portion abutting undersurface portions of bothvalves, a guide stem portion extending axially from the base portionhaving slidable movement in the guide bore and extending between thevalves and in close relation thereto, a spring seated in each wellpressing upwardly against the underside of the base portion of therelated guide member so as to yieldably hold the valvesfby means of thebase portion seated over the intake channels, the base portion of eachguide member being forcefully movable into its corresponding well uponopening of the valves, each well having a at level bottom surface, andthe base portion of each guide member having a complementary flatundersurface impactable against the bottom surface of its well uponopening of the valves.

2. The improvement as in claim 1, wherein the diameter of each well isslightly greater than that of the base portion of the related guidemember.

3. The improvement as in claim 2, wherein the bottom of the annularchannel is llat and level, the valves overhang the base portion of eachguide member slightly beyond the radius of the Well, and the axial depthof each well corresponds to the axial thickness of the base portion ofthe related guide member, whereby the upper faces of the base portionsof the guide members are uSh with the bottom of the annular channel whenthe base portions are fully received in t-he wells and the valvesoverlie the bottom of the annular channel.

4 The improvement as in claim 1, wherein the springs are substantiallyidentical and the strength of the several springs is just enough to holdthe valves seated when the compressor is at rest.

5. The improvement as in claim 1, wherein the axial depth of each wellcorresponds to that of the base portion of the related guide member, thespring is a coil spring received at its upper end in a shallow annulargroove at the underside of the base member and is seated at its oppositeend in an annular groove at the bottom of the well, the latter groovebeing of sufficient depth to fully receive the spring when the baseportion of the guide member is fully received in the well.

6. The improvement as in claim 1, wherein the guide member is formed ofmaterial having an inherent slippery and greasy surface, and isresistant to high temperature.

7. The improvement as in claim 1, wherein the guide member is formed ofglass lled plastic material, the plastic material being of a naturehaving a property of being slippery and greasy to the touch, andresistant to high temperatures in a range of 450-500 degrees F.

No references cited.

2o WILLIAM F. ODEA, Primary Examiner.

D. I. ZOBKIW, Assistant Examiner.

1. IN A VALVE UNIT FOR A PISTON TYPE AIR COMPRESSOR, COMPRISING A VALVESEAT MEMBER HAVING AN INNER LEVEL FACE AND A PAIR OF CONCENTRIC AIRINTAKE CHANNELS RECESSED IN SAID FACE, A KEEPER MEMBER COMPLEMENTING THESEAT MEMBER HAVING AN INNER LEVEL FACE AND HAVING AN ANNULAR CHANNELRECESSED THEREIN IN OPPOSED PARALLEL RELATION TO THE INTAKE CHANNELS,AND A PAIR OF CONCENTRICALLY ARRANGED RING PLATE VALVES AXIALLY MOVABLEIN THE ANNULAR CHANNEL TO OPEN AND CLOSED CONDITION OVER THE INTAKECHANNELS, THE IMPROVEMENT COMPRISING: A PLURALITY OF WELLS SPACEDCIRCUMFERENTIALLY EQUALLY APART AT THE BOTTOM OF THE ANNULAR CHANNEL OFTHE KEEPER MEMBER AND EACH CENTERED RELATIVE TO THE INTAKE CHANNELS, ASEPARATE GUIDE CENTERED AXIAL WITH EACH WELL FORMED IN THE SEAT MEMBERBETWEEN THE INTAKE CHANNELS, A VALVE GUIDE ASSOCIATED WITH EACH WALLHAVING AN ANNULAR BASE PORTION ABUTTING UNDERSURFACE PORTIONS OF BOTHVALVES, A GUIDE STEM PORTION EXTENDING AXIALLY FROM THE BASE PORTONHAVING SLIDABLE MOVEMENT IN THE GUIDE BORE AND EXTENDING BETWEEN THEVALVES AND IN CLOSE RELATION THERETO, A SPRING SEATED IN EACH WELLPRESSING UPWARDLY AGAINST THE UNDERSIDE OF THE BASE PORTION OF THERELATED GUIDE MEMBER SO AS TO YIELDABLY HOLD THE VALVES BY MEANS OF THEBASE PORTION SEATED OVER THE INTAKE CHANNELS, THE BASE PORTION OF EACHGAUIDE MEMBER BEING FORCEFULLY MOVABLE INTO ITS CORRESPONDING WELL UPONOPENING OF THE VALVES, EACH WELL HAVING A FLAT LEVEL BOTTOM SURFACE, ANDTHE BASE PORTION OF EACH GUIDE MEMBER HAVING A COMPLEMENTARY FLATUNDERSURFACE IMPACTABLE AGAINST THE BOTTOM SURFACE OF ITS WELL UPONOPENING OF THE VALVES.